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Power 3 uses Updated August 10, 2026

AC Power Calculator

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Select Phase
To Find
Power Factor Angle
°
Voltage
volts
Current
Amps
Power
watt

This AC power calculator finds the real, apparent, and reactive power of a single-phase AC load from voltage, current, and power factor. Enter the values above.

Formulas

Apparent S = V × I           (VA)
Real     P = V × I × PF      (W)
Reactive Q = V × I × sinφ   (VAR)

Example

230 V, 5 A, PF 0.8: S = 1150 VA, P = 920 W, Q = 690 VAR.

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Frequently Asked Questions

How do I calculate AC power?

Multiply voltage by current for apparent power (VA), then by power factor for real power (W).

What is reactive power?

It is the power that oscillates between source and load without doing work, measured in VAR.

What is the difference between W and VA?

Watts is real power that does work; VA is apparent power. They are equal only at unity power factor.

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